A216916
Triangle read by rows, T(n,k) for 0<=k<=n, generalizing A098742.
Original entry on oeis.org
1, 1, 1, 3, 3, 1, 9, 12, 6, 1, 33, 51, 34, 10, 1, 135, 237, 193, 79, 15, 1, 609, 1188, 1132, 584, 160, 21, 1, 2985, 6381, 6920, 4268, 1510, 293, 28, 1, 15747, 36507, 44213, 31542, 13576, 3464, 497, 36, 1, 88761, 221400, 295314, 238261, 120206, 37839, 7231, 794
Offset: 0
[0] [1]
[1] [1, 1]
[2] [3, 3, 1]
[3] [9, 12, 6, 1]
[4] [33, 51, 34, 10, 1]
[5] [135, 237, 193, 79, 15, 1]
[6] [609, 1188, 1132, 584, 160, 21, 1]
[7] [2985, 6381, 6920, 4268, 1510, 293, 28, 1]
[8] [15747, 36507, 44213, 31542, 13576, 3464, 497, 36, 1]
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def A216916_triangle(dim):
T = matrix(ZZ,dim,dim)
for n in range(dim): T[n,n] = 1
for n in (1..dim-1):
for k in (0..n-1):
T[n,k] = T[n-1,k-1]+(k+1)*T[n-1,k]+(k+2)*T[n-1,k+1]
return T
A216916_triangle(9)
A074664
Number of algebraically independent elements of degree n in the algebra of symmetric polynomials in noncommuting variables.
Original entry on oeis.org
1, 1, 2, 6, 22, 92, 426, 2146, 11624, 67146, 411142, 2656052, 18035178, 128318314, 954086192, 7396278762, 59659032142, 499778527628, 4341025729290, 39035256389026, 362878164902216, 3482882959111530, 34472032118214598
Offset: 1
G.f. = x + x^2 + 2*x^3 + 6*x^4 + 22*x^5 + 92*x^6 + 426*x^7 + 2146*x^8 + ...
m{1} = x1 + x2 + x3 + ..., so a(1) = 1.
m{1,2} = x1 x2 + x2 x1 + x2 x3 + x3 x2 + x1 x3 + ..., m{12} = x1 x1 + x2 x2 + x3 x3 + ... where m{1} m{1} = m{1,2} + m{12}, so a(2) = 2-1 = 1.
m{1,2,3} = x1 x2 x3 + x1 x2 x4 + x1 x3 x4 + ..., m{12,3} = x1 x1 x2 + x2 x2 x1 + ..., m{13,2} = x1 x2 x1 + x2 x1 x2 + ..., m{1,23} = x1 x2 x2 + x2 x1 x1 + ..., m{123} = x1 x1 x1 + x2 x2 x2 + ... and there are 3 independent relations among these 5 elements m{12} m{1} = m{123} + m{12,3}, m{1} m{12} = m{123} + m{1,23}, m{1} m{1,1} = m{1,2,3} + m{12,3} + m{13,2} so a(3) = 5-3 = 2.
- D. E. Knuth, The Art of Computer Programming, Vol. 4, Section 7.2.1.7, Problem 26.
- Vaclav Kotesovec, Table of n, a(n) for n = 1..573 (terms 1..100 from T. D. Noe)
- Vsevolod E. Adler, Set partitions and integrable hierarchies, arXiv:1510.02900 [nlin.SI], 2015.
- Marcelo Aguiar and Swapneel Mahajan, On the Hadamard product of Hopf monoids
- Jean-Luc Baril, Toufik Mansour, Armen Petrossian, Equivalence classes of permutations modulo excedances, 2014.
- Nantel Bergeron, Christophe Reutenauer, Mercedes Rosas, and Mike Zabrocki, Invariants and Coinvariants of the Symmetric Group in Noncommuting Variables, arXiv:math/0502082 [math.CO], 2005.
- Daniel Birmajer, Juan B. Gil, Michael D. Weiner, A family of Bell transformations, arXiv:1803.07727 [math.CO], 2018.
- David Callan, On permutations avoiding the dashed patterns 32-41 and 41-32, arXiv preprint arXiv:1405.2064 [math.CO], 2014
- William Y.C. Chen, Teresa X.S. Li, David G.L. Wang, A Bijection between Atomic Partitions and Unsplitable Partitions, Electron. J. Combin. 18 (2011), no. 1, Paper 7.
- Alice L.L. Gao, Sergey Kitaev, and Philip B. Zhang, On pattern avoiding indecomposable permutations, arXiv:1605.05490 [math.CO], 2016.
- Ignas Gasparavičius, Andrius Grigutis, and Juozas Petkelis, Picturesque convolution-like recurrences and partial sums' generation, arXiv:2507.23619 [math.NT], 2025. See p. 27.
- Meng He, J. Ian Munro, S. Srinivasa Rao, A Categorization Theorem on Suffix Arrays with Applications to Space Efficient Text Indexes, SODA 2005, Definition 2.2.
- Aoife Hennessy, A Study of Riordan Arrays with Applications to Continued Fractions, Orthogonal Polynomials and Lattice Paths, Ph. D. Thesis, Waterford Institute of Technology, Oct. 2011.
- Martin Klazar, Bell numbers, their relatives and algebraic differential equations
- Martin Klazar, Bell numbers, their relatives and algebraic differential equations, Journal of Combinatorial Theory, Series A, Volume 102, Issue 1, April 2003, pp. 63-87.
- Margarete C. Wolf, Symmetric Functions of Non-commutative Elements, Duke Math. J., 2 (1936), 626-637.
- Chunyan Yan and Zhicong Lin, Inversion sequences avoiding pairs of patterns, arXiv:1912.03674 [math.CO], 2019.
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T := proc(n, k) option remember; local j;
if k=n then 1
elif k<0 then 0
else k*T(n-1,k) + add(T(n-1,j), j=k-1..n-1)
fi end:
A074664 := n -> T(n, 0);
seq(A074664(n), n=0..22); # Peter Luschny, May 13 2014
-
nmax = 23; A087903[n_, k_] := A087903[n, k] = StirlingS2[n-1, k] + Sum[ (k-d-1)*A087903[n-j-1, k-d]*StirlingS2[j, d], {d, 0, k-1}, {j, 0, n-2}]; a[n_] := Sum[ A087903[n, k], {k, 1, n-1}]; a[1] = 1; Table[a[n], {n, 1, nmax}](* Jean-François Alcover, Oct 04 2011, after Philippe Deléham *)
Clear[t, n, k, i, nn, x]; coeff = ConstantArray[1, 23]; mp[m_,e_] := If[e==0, IdentityMatrix@ Length@ m, MatrixPower[m, e]]; nn = Length[coeff]; cc = Range[nn]*0 + 1; Monitor[ Do[Clear[t]; t[n_, 1] := t[n, 1] = cc[[n]];
t[n_, k_] := t[n, k] = If[n >= k,
Sum[t[n - i, k - 1], {i, 1, 2 - 1}] +
Sum[t[n - i, k], {i, 1, 2 - 1}], 0];
A4 = Table[Table[t[n, k], {k, 1, nn}], {n, 1, nn}];
A5 = A4[[1 ;; nn - 1]]; A5 = Prepend[A5, ConstantArray[0, nn]];
cc = Total[
Table[coeff[[n]]*mp[A5, n - 1][[All, 1]], {n, 1,
nn}]];, {i, 1, nn}], i]; cc
(* Mats Granvik, Jul 11 2015 *)
-
{a(n) = if( n<0, 0, polcoeff( 1 - 1 / serlaplace( exp( exp( x + x * O(x^n)) - 1)), n))};
-
x='x+O('x^100); B=exp(exp(x) - 1); Vec( 1-1/serlaplace(B)) \\ Joerg Arndt, Aug 13 2015
A116155
Triangle T(n,k) defined by: T(0,0)=1, T(n,k)=0 if k < 0 or k > n, T(n,k) = T(n-1,k-1) + k*T(n-1,k) + Sum_{j>=1} T(n-1,k+j).
Original entry on oeis.org
1, 0, 1, 1, 1, 1, 2, 3, 3, 1, 7, 9, 10, 6, 1, 26, 33, 36, 29, 10, 1, 109, 135, 145, 134, 70, 15, 1, 500, 609, 645, 633, 430, 146, 21, 1, 2485, 2985, 3130, 3142, 2521, 1182, 273, 28, 1, 13262, 15747, 16392, 16561, 14710, 8733, 2849, 470, 36, 1
Offset: 0
Triangle begins:
1;
0, 1;
1, 1, 1;
2, 3, 3, 1;
7, 9, 10, 6, 1;
26, 33, 36, 29, 10, 1;
109, 135, 145, 134, 70, 15, 1;
500, 609, 645, 633, 430, 146, 21, 1;
2485, 2985, 3130, 3142, 2521, 1182, 273, 28, 1;
13262, 15747, 16392, 16561, 14710, 8733, 2849, 470, 36, 1;
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T[0, 0]:= 1; T[n_, k_]:= If[k<0 || k>n, 0, T[n-1, k-1] + k*T[n-1, k] + Sum[T[n-1, k+j], {j, 1, n-k-1}]]; Table[T[n, k], {n, 0, 10}, {k, 0, n}]//Flatten (* G. C. Greubel, May 10 2019 *)
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{T(n,k) = if(k==0 && n==0, 1, if(k<0 || k>n, 0, T(n-1, k-1) + k*T(n-1, k) + sum(j=1,n-k-1, T(n-1, k+j))))}; \\ G. C. Greubel, May 10 2019
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